The application of a computer data acquisition system for a new high temperature tribometer

The two data acquisition computer programs are described which were developed for a high temperature friction and wear test apparatus, a tribometer. The raw data produced by the tribometer and the methods used to sample that data are explained. In addition, the instrumentation and computer hardware and software are presented. Also shown is how computer data acquisition was applied to increase convenience and productivity on a high temperature tribometer

Opportunistic use of a wool-like artificial material as lining of Tit (Paridae) nests

The lining material is a key element of bird nests primarily serving as insulation for the adult, eggs and/or chicks but collection of such material will have an energetic cost. This study investigated the nest building effort of four species of tit (Paridae) in an English wood by determining the use of colored, wool-like artificial nest lining material over the period 2000-2010. The distances that birds carried the material from source to nest was recorded for each nest as an indirect measure of the energetic cost of collection of nest material by individual birds. Birds did not always use nest material from the nearest source to their nest and some birds collected material from 2, 3 or 4 well-separated sources. There was no detectable color preference in choice of material and few birds would travel more than 200 m to gather the material. Use of the material appeared to depend on the species. Within defined areas around material dispensers not all individual Great Tits (Parus major) used the artificial material and, for all species examined, the proportion of birds using the material declined with increasing distance between source and nest. Use of artificial material suggested that selection of nest materials was probably opportunistic but also reflected the preference of these species for a wool-like nest-lining

Money, sticky wages, and the Great Depression

This paper examines the ability of a simple stylized general equilibrium model that incorporates nominal wage rigidity to explain the magnitude and persistence of the Great Depression in the United States. The impulses to our analysis are money supply shocks. The Taylor contracts model is surprisingly successful in accounting for the behavior of major macroaggregates and real wages during the downturn phase of the Depression, i.e., from 1929:3 through mid-1933. Our analysis provides support for the hypothesis that a monetary contraction operating through a sticky wage channel played a significant role in accounting for the downturn, and also provides an interesting refinement to this explanation. In particular, both the absolute severity of the Depression's downturn and its relative severity compared to the 1920-21 recession are likely attributable to the price decline having a much larger unanticipated component during the Depression, as well as less flexible wage-setting practices during this latter period. Another finding casts doubt on explanations for the 1933-36 recovery that rely heavily on the substantial remonetization that began in 1933.Money supply ; Wages ; Depressions

Subsurface tropical Pacific nitrogen isotopic composition of nitrate: Biogeochemical signals and their transport

We report measurements of the nitrogen isotopic composition of nitrate (the δ15N of NO3−) across the equatorial Pacific, for zonal transects from 165°E to 95°W and meridional transects across 95° and 110°W. The δ15N of NO3− is similar in the equatorial thermocline (≈100 m) and intermediate depth waters (≈150 to 600 m), averaging (7.1 ± 0.3)‰ and (7.1 ± 0.1)‰, respectively. These values are more than 2‰ higher than subthermocline waters of the Southern and Atlantic Oceans and are ≈1‰ higher than putative source waters in the high latitude South Pacific (Subantarctic Mode Water, SAMW). The combined constraints of nitrate concentration and δ15N of NO3−in the equatorial Pacific require (1) lateral exchange between the high‐latitude source waters and the zones of denitrification in the eastern tropical Pacific and (2) the accumulation of remineralized nutrients at depth. The zonal uniformity of the subsurface equatorial Pacificδ15N of NO3− indicates rapid transport within the equatorial zone, which works to homogenize the δ15N of NO3− across the Pacific basin. Against this backdrop of high δ15N of NO3−in the tropical Pacific, we find a discrete off‐equatorial core of lowerδ15N of NO3− (5.5 ± 0.3)‰ concentrated at 5°S and 150 to 200 m along the 110° and 95°W transects and in apparent association with the Southern Subsurface Counter Current (SSCC). We propose that the remineralized products of nitrogen fixation, at the source of the SSCC in the western south Pacific, are the origin of the low δ15N of NO3− in these waters

Estimation of trailer off-tracking using visual odometry

High Capacity Vehicles (HCVs) have been shown to be highly effective in reducing emissions associated with road freight transport. However, the reduced manoeuvrability of long vehicles often necessitates the use of active trailer steering. Path-following trailer steering systems are very effective in this regard, but are currently limited to on-highway applications due to the manner in which trailer off-tracking is estimated. In this work, a novel trailer off- tracking measurement concept is introduced which is independent of wheel slip and ground surface conditions, and requires no additional sensor measurements or parameter data from the tractor. The concept utilises a stereo camera pair affixed to the trailer and a visual odometry-based algorithm to calculate off-tracking. The concept was evaluated in detailed simulation and full-scale vehicle tests, demonstrating its feasibility and highlighting some important characteristics. RMS measurement errors of 0.11-0.12 m (3.3-3.6%) were obtained in a challenging visual environment.CSIR, South Africa; Cambridge Commonwealth, European and International Trust, UK; Cambridge Vehicle Dynamics Consortium

Experimental Analysis of Nest Predation: Effects of Habitat and Nest Distribution

Depredation of artificial avian ground nests was studied in 1994 and 1995 on cool-season and warm-season grasslands in western New York State. The study examined the effects of habitat type and distance from forested edge on nest success in adjacent fields. Two experiments were conducted. The first examined the effects of nest distribution on nest success. Experimental predation rates were highest at the field-forest boundary, although there was no correlation between predation rate and distance from edge. Overall predation rates for cool-season grasslands differed significantly between years, with predation rates being higher during the 1995 field season. The second experiment examined the effects of dense nesting cover on nest success. Predation rates for nests in dense nesting cover varied among distance classes in 1995 but not in 1994; predation rates were also higher in 1995 than in 1994. Experimental rates of nest predation were similar in pasture/cool-season grasslands and warm-season grasslands in both years, suggesting that dense cover did not improve productivity of ground-nesting birds. Indirect evidence suggested that the primary predators along the forest-field boundaries were mammals, with birds and small mammals most frequently depredating nests away from the edge. This study suggests that dense nesting cover does not increase nesting success for small passerines on our study site

H-alpha Imaging with HST+NICMOS of An Elusive Damped Ly-alpha Cloud at z=0.6

Despite previous intensive ground-based imaging and spectroscopic campaigns and wide-band HST imaging of the z=0.927 QSO 3C336 field, the galaxy that hosts the damped Ly-alpha system along this line-of-sight has eluded detection. We present a deep narrow-band H-alpha image of the field of this z=0.656 damped Ly-alpha absorber, obtained through the F108N filter of NICMOS 1 onboard the Hubble Space Telescope. The goal of this project was to detect any H-alpha emission 10 times closer than previous studies to unveil the damped absorber. We do not detect H-alpha emission between 0.05'' and 6'' (0.24 and 30 $h^{-1}$ kpc) from the QSO, with a 3-sigma flux limit of $3.70 \times 10^{-17} h^{-2}$ erg/s/cm^2 for an unresolved source, corresponding to a star formation rate (SFR) of $0.3 h^{-2}$ M_sun/yr. This leads to a 3-sigma upper limit of 0.15 M_sun/yr/kpc^2 on the SFR density, or a maximum SFR of 1.87 M_sun/yr assuming a disk of 4 kpc in diameter. This result adds to the number of low redshift damped Ly-alpha absorbers that are not associated with the central regions of Milky-Way-like disks. Damped Ly-alpha absorption can arise from high density concentrations in a variety of galactic environments including some that, despite their high local HI densities, are not conducive to widespread star formation.Comment: 18 pages, 3 figures. Replaced to match published version in ApJ, 550, 585 (Apr 1 2001